private void button1_Click(object sender, EventArgs e)
{
serialPort1.Open();
serialPort1.DataReceived += new SerialDataReceivedEventHandler(sp5_DataReceived);
serialPort1.Write(cmdByte, 0, 8);
}
void sp5_DataReceived(object sender, SerialDataReceivedEventArgs e)
{
Thread.Sleep(500);
System.Windows.Forms.Control.CheckForIllegalCrossThreadCalls = false;
SerialPort port = (SerialPort)sender;
byte[] buf = new byte[50];
int len = port.Read(buf, 0, buf.Length);
MessageBox.Show(len.ToString());
serialPort1.DataReceived -= new SerialDataReceivedEventHandler(sp5_DataReceived);
port.Close();
}